And one-fourth to herman c



F. HACHMANN.

SPARK PLUG.

APPLICATION FILED APR-1.1,19I9.

1,3 1,326, Patented Dec. 7,1920.

2 SHEETS-SHEET I- F. HACHMANN.

SPARK PLUG.

APPLICATION FILED'APR. H, 1919.

1,361,326, Patented Dec: 7,1920

2 SHEETS-SHEET 2.

56 59 gig 32 UNITED STATES PATENT OFFICE.

FREDERICK HACEMANN, OF ST. LOUIS, MISSOURI, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, OF THREE-EIGHTI-IS TO DAVIDEYE. EIUTCI-IINSON, 0F FERGUSON, MIS- SOURI. ONE-SIXTEENTH T0 CHAUNCEY It. WATSON, ONE-SIXTEENTH TO PHILIP E. i

MOODY, ONE-SIXTEENTH TO ELIJAH E. FRASER,

ALL OF DETROIT, MICHIGAN,

AND ONE-FOURTH TO HERMAN o. STIFEL, or s'r. LOUIS, MISSOURI.

SPARK-PLUG.

Specification of Letters Patent. 7 Pate t d D 7 1920 Application filed April 11, 1919. Serial No. 289,238.

To all whom it may concern p Be it known that I, FREDERICK HACH- MANN, a citizen of the United States, and resident of the city of St. Louis and State of Missouri, have invented certain new and use- I ful Improvements in Spark-Plugs, of which the following is aspecification containing a full, clear, and exact description, reference being had to accompanying drawings, form.- ing a part thereof.

This invention relates to spark plugs and has for its primary object a spark plug having an auxiliary spark gap which is nclosed in a sealed chamber, thus intensifying the spark, the air in this chamber becoming highly electrified and acting as a storage for the electric current.

A further object is to construct a spark plug, the upper portion of which is dipped in insulating material and then baked so that, in case of moisture, there Wlll be no short circuit of the plug.

Another object is to construct a spark plug wherein the grounded terminal or electrode extends almost completely around the casing, thereby making a much better connection between the casing and the grounded electrode than is possible in the spark plugs of the present construction.

In the drawings: 7

Figure 1 is a side elevation of my device.

Fig. 2 is a vertical cross sectional ylew of the same.

Fig. 3 is a bottom plan view.

sulating section. I Fig. 5 is a bottom plan view of the same. Fig. 6 is a top plan view of the lower insulating section, showing the groove formed therein for the reception of additional 1nsulating material.

Fig. 7 is a bottom plan view of the same. Fig. 8 is a perspective view of the grounded electrode made use of.

Fig. 9 is an enlarged fragmental section,

showing the method of securing the grounded electrode in the shell or casmg,

Fig. 10 is a view of a modlfied form of my device. 4

Fig. 11 is a vertical cross sectional new of the same. i

Fig. 12 is a top plan view of the Water :hedding nut made use of in my modificagig. 13 is a bottom plan view of F 11, an I Fig. 14 is a plan view of the modified grounded electrode.

lieferring to the drawings 15 indicates a casing which is provided near its lower end wlth screw threads 16, these screw threads being employed for securing the plug to the explosion chamber of an engine, the upper end being provided with faces 19 so as to allow the engagement of a wrench for screwing the body or casing 15 into the cylinder or explosion chamber.

The casing 15 is provided with a screw threaded bore 20 in which the packing or tightening nut 21 is inserted. The casing 15 is further provided with a bore 22 which bore is of less diameter than the bore 20, these bores 20 and 22, being concentric, form the shoulder 23. In this shoulder 23 is placed a washer or gasket 24 which is constructed of heat resisting and insulating material. On the washer 24 rests the flange 25 of the lower electrode carrying body 26. This body is constructed of porcelain, glass or any other non-conducting and heat resisting material.

The flange 25 is provided with a semicircular groove 27 in which a gasket 28 is placed, this gasket being of heat resisting and insulating material. The lower portion of this carrying body is provided with Fig. 4; is a top plan view of the upper inr and 11. The upper portion of the body 26 is provided with a bore 30. Through this bore, the electrode 31 passes and is cemented therein.

Surrounding the electrode 31 and extending above the flange 25, I provide a conical projection 32, the object of which is to provide an extended hearing or brace for the upper end of the electrode 31 and possibly confine the electrified air in the chamber 39 around the exposed end of said electrode.

Resting on the gasket 28, I provide a member 33, this member being conical in shape and is provided on its lower end with a flange 3i which rests on the gasket 28. I

On the upper edge of the flange 34 is placed a washer or gasket 35 which is constructed of heat resisting and insulating material andon this washer or gasket, the end of the nut 21 rests, thus binding the members 26 and 33 securely together. On the member 33, I form a flange 36 on which is placed a washer 37, this washer beingof any absorbent material so that, when the nut 29 is forced home, a water tight joint will be provided and prevent leakage of mo1s'-- ture within the plug.

The nut 21 is further provided with an extending flange 38. This-flange'is'prefen ably circular in form and acts as a water shed, soastoprevent short oircuitingof the plug in case moisture comes in contact with the plug;

The member 33 is provided with a conical cavity 39which acts-as a storage chamber and condenser for the primary spark. Withinthis chamber and extending through the member 33 is the electrode 40, this electrode" being providedwith' a ball shaped terminal 41, which terminal'is located inthe cavity 39,:theupper end being provided with screw threads 42 over which a binding'nut 43 is located, this securing the electrode 40 inthe member 33.

Over the upper end of-the electrode'is secured a binding post 4A which is provided with a knurled portion l5 and a plug' 16' so th'at either a spring-socket or a U-shaped terminal on the conductor wire can be made use-of, when theplug is-connected up.

The lower end of the casing 15 is provid ed with a" groove 47in which the groundedelectrode 48*is seated, this electrode being provided with an extending portion 49, so as-to' create a gap between it and the electrode 31". In order tosecure theieleotrode- 48* within the groove a7; a flaringv tool is made use of and the inner edgeof the casing v 15 flared as indicated by thenumeral 50,

so 'asto securely liold'the electrodein' placer By this means, I achieve a. much better "contact between the grounded electrode and the casing than is possib'lein structures of tica-las shown in Fig; 2, but the nut 21 isplacedbelow a water shedding. flange 51,,

this flange-being fully illustrated in Figs. 10, 11, 12-and 13 and'is dipped into a bath of porcelain or other insulating material and. extends'rbeyond the faces formed'on the casing' 15, so'th'at' any moisture willd'rip clear of the faces 19.

The upper and lower faces ofthe water shedding flange are inclined as indicated by the numerals 52 and 53 so as to prevent any moisture which may lodge thereon from running over the side face of the nut and cause a short circuit in'the spark plug.

The end 54 of the electrode 36 is bent as indicatedin Figs. 10, 11,12 and 13 so as to form a spark gap between it and the electrode 55, this electrode being ring shaped and being crimped within the lower portion ofthe casing 15. This crimping means is accomplished by the same method as described previously.

The ring 55 is. constructed of material which does not deteriorate, by having the spailcpass'fromit In other words, the

surface of the ring is'not burned away,

when the spark-leaps the gap. This has been-found'to be a common failingwhere the casingitselfwas made use of as an electrode; v

As previously pointed out, the cavity 39 acts as a" chamber for the electrified air caused by the primary spark. If'it is found in practice that the electrified air in this chamber'becomes' heatedlto such an extent that the elasticpacking will ,nottake care of'the undue expansion, I may form a vent in'thecasing'15adjacent the space or openin between the members 26 and 33'.

aving fully described by invention,

. what I claimis 2 1 A spark plug comprising a casing providedwith an internal shoulder, a circular grounded electrode mounted in the lower end of sa d casing, an insulating member provided with a flange mounted'm sa1d casmg,a

gasket mounted in the casing and interposed between the shoulder formed in thecasing and the'fiang'e on the insulatingmemb'er, an' electrode mountedin said insulating member 'andpr'ojecting above the upper endthereof, an upper insulatingflmemberprovided on its lower-end with a downwardly and outwardly flaring chamber, ,and'hav'ing formed around'its lower ends. flange, and.

above said flange; and spaced apart therefrom a second. flange, gaskets mounted on the upper" insulator and 'seated Yon each fiangethereofiand a jam nut screw seated insulating members located within the:

casing. and spaced apart, a compressible gasket locatedbetween-the insulating memhere, a fastening nut for securing said members within the casing, an outwardly extending flange formed integral with said nut and acting as a water-shed, an electrode secured in each of said insulating members, and meanslocated around one of the lnsua lators and within the nut for preventing the entrance or" moisture into the interior of the plug.

3. A spark plug comprising a hollow screw threaded casing, a shoulder formed in said casing, a gasket located on said shoulder, an insulating member located within said casing, a flange formed around the upper end of said insulating member and resting on the gasket, a second gasket mounted on said flange opposite the first mentioned gasket, a second insulator pro vided with a downwardly flaring central opening resting on said second mentioned gasket, a pair of parallel spaced apart flanges formed around the outer surface of said second mentioned insulator, a packing nut having a counterbore adapted to be screwed withinthe casing, a pair of gaskets mounted on the flanges and adapted to coni tact with thenut, the upper gasket and nut forming a water tight joint between the interior of the plug and the outside thereof, an electrode secured within each insulator and a projecting flange formed on the nut,

FREDERICK HAOI-IMANN.

Witnesses:

EDWARD E. LoNGAN, ELIZABETH GARTALL. 

